Utilizing Green Infrastructure as a

TMDL Implementation Tool: A Case

Study in the Kids Creek Watershed

Troy Naperala

June 2016

Tributary to Boardman River with watershed

primarily composed of commercial, residential

and institutional land uses.

Project Location

Data Collected

• Qualitative aquatic organism and habitat data

• Limited VOC samples

• Limited water column samples for metals and

nutrients

• Observations of flashy flows and increased

turbidity

• Eroding bank inventory

• Historic information/ other sources

Kids Creek

Impairment

• Impaired Waters List for

Aquatic Life and Wildlife

• Issues:

– “Poor” macroinvertebrate

community 2003, 2008

– Sedimentation

– Flow regime alteration

– Storm water quality and

quantity

• TMDL not complete

Impaired Reach ~2 miles

Flashy Flows from Stormwater

Peak

Discharg

e (CFS)

Percent

Change

Total

Volume

(Ft.3)

Percent

Change

Existing 28.2 - 183888 -

25% IC 8.25 -71% 58572 -68%

10% IC 4.36 -85% 28332 -85%

0% IC 0.69 -98% 6768 -96%

Sediment Load from Stormwater

SSCF (mg/L) SSCC (mg/L)

Dry Weather

Open Channel 12.0 5.7

Collection System 3.3 12.9

Wet Weather

Open Channel 14.5 21.8

Collection System 11.5 245.1

Examples of

watershed

sediment

Impervious Cover: Impacts on Stormwater

Blue: Control

Red: Test

Can GI/ LID Reduce Volume?

Planning Approach

Watershed

Scale

Neighborhood

Scale

Site

Scale

• Goals and Targets

• Regulatory Drivers

• Public Engagement

• Budget (Capital and

O&M)

• Watershed

Characterization

• Prioritize Locations

• Prioritize GI Types

• Alternatives

• Implementation Period

• Verify Physical

Suitability of Sites

• Collect Data

• Public Engagement

• Budget (Capital and

O&M)

• Select Locations

• Select GI Types

• Develop Design and

Construction Schedule

• Collect Data

• Infiltration

• Utilities

• Contamination

• Cost Estimating

• Implement Design and

Construction Schedule

Develop plan to meet

goals within budget

and other constraints

Refine projects,

project locations, and

costs

Engineer, design,

construct, and

maintain

Ou

tpu

ts

The Solution: Stream Restoration and LID

Cowell Family Cancer Center

• Stream Daylighting – 1,275 feet of new channel

replacing 900 feet of enclosed piping

• New 39,700 sq. ft. floodplain area.

• Reduction of 72,000 sq. ft. of impervious area.

• 26,000 cubic feet of infiltration trench

• 750 sq. ft. raingarden

• 3,179 sq. ft. of green roof

Restoration of Tributary AA to Kids Creek

2012 2015

Cowell Cancer Center Green Roof

Cowell Cancer Center Green Roof

Cowell Cancer Center Green Roof

Cowell Cancer Center Green Roof

Cowell Cancer Center Green Roof

Building 29

• 3 planter boxes added

– 600 cubic feet of

storage

– Capture 2,000 sq.

ft. of roof top.

• Pervious Pavement

– 1,310 sq. ft.

• 1 large bio swale

Planter Box Detail

Pervious Pavement

Planned BMPs

• 90○ Creek/ Floodplain Restoration

• Medical Campus Drive Infiltration Practices

• Elmwood Wetlands

• Helipad bio infiltration

• Green Roof

The Solution: Stream Restoration and LID

90○ Creek/ Floodplain Restoration

Adjust channel profile and

sinuosity

Elmwood Wetland

Medical Center Drive

Elmwood Street SOM Building

Future BMPs

• Focus on 14th Street Sub Watershed

– Rain Gardens

– Underground infiltration

– Channel/ floodplain restoration

– Pervious Pavement

14th Street Watershed

14th Street Watershed (preliminary!)

Green Infrastructure Unit Cost/Unit

# units obtainable with

$1,000,000

Amt. of BMPs required to

hit 25% target model

results

Rain Garden Area (sq. foot)

$20.00 -

$25.00 40,000 -50,000 sq. ft. 59,677 sq. ft.

Inline Detention/

Infiltration Volume (cb. Ft.) $8-12 83,333– 125,000 cubic ft. 11,583 cubic ft.

Rain Barrel Each $100.00 10,000 barrels 10,510 barrels

Tree Box Area (sq. foot) $30 - $40 25,000 – 33,333 sq. ft. 184,694 sq. ft.

Pervious Pavement Area (sq. foot) $8 - $10 100,000 – 125,000 sq. ft. 83,200 sq. ft.

Caveats: • BMPs need to be spread throughout watershed • Costs are preliminary and will vary based on the site

Planned BMP System: Infiltration Trenches Key Points:

• Know what materials are

available locally

• Review and question all as-built

drawings

Summary and Conclusions

• Stream restoration, green roofs, raingardens, planter

boxes, wetlands! Volume and pollutant reduction.

• Success! Through a collaborative and sustained

process, a lot of BMPs have been installed and more are

planned.

• Up front planning uses estimates of volume and load

reduction to prioritize implementation activities.

– SWMM modeling used to assess hydrologic impacts

of BMPs – nearly 90% reduction in volume possible!

– Large sediment sources easily mitigated

Summary and Conclusions

• Benefits of installed BMPs not being measured

– Impaired water will be evaluated

• BMP Costs

– Approximately $4.3 spent to date

– Another $0.5M planned in the next 18 months.

– $1.5M proposed in future work

• Future work will also need to focus on repairing the

instream habitat.

Questions?

Troy Naperala

Troy.Naperala@aecom.com